1. Field of the invention
The invention relates to an electroweldable socket of thermoplastic material manufactured by providing said socket internally, at least locally, with a lining of electrically conductive material near the inner wall of the socket. A socket as used herein means of course any pipe fitting which may be used for connecting such a pipe fitting with a pipe end by electroheat welding.
2. Description of the prior art
Two plastic pipes are frequently connected by sealingly placing a socket over the two pipe ends approaching each other. In the case of thermoplastic pipes it is known to fuse together the outer wall part of the pipe and the inner wall part of the socket by connecting an electrically conductive lining in the inner wall of the socket to an electrical source.
Use has been made in this case of a spiral, wound in a manner corresponding to a helical line, of an electrically conductive wire, which wire is for example pulled off the two ends of the socket in order to connect the latter with an electrical source, so that the wire heats the plastic in the vicinity of the spiral and fuses this plastic. Uptil now these sockets are manufactured in a complicated manner by on the one hand starting from an injection moulding process and on the other hand taking into account that the socket had to shrink so that the materials of socket and pipe are united in a satisfactory manner. These sockets accordingly are relatively expensive while the manufacturing time is relatively long.